26 G 5 . REPORT OF PROGRESS. I. C. WHITE. 



Bowlders of metamorphic rocks are found only in the ex- 

 treme northwest corner of Susquehanna county. Every- 

 where else the Drift-materials are derived from the rocks of 

 the neighborhood, or from outcrops in southern New York. 



Granite and gneissoid bowlders are confined to Apolacon, 

 Choconut, Middletown and Rush townships of Susque- 

 hanna county ; are always rounded and polished ; but are 

 of diminutive size compared with the same class of bowl- 

 ders in the western part of the state. All that I noticed 

 were less than two feet in diameter. In Beaver, Lawrence 

 and Mercer counties it is a common thing to find them 8' to 

 10' diameter. 



This inferiority in the size of Susquehanna county bowl- 

 ders may indicate greater distance from the source ; or more 

 probably a less massive condition of the mother rocks of a 

 totally different original locality.* 



Salt Lick creek moraine : — Good exposures of Drift are 

 infrequent. One of the best is about two miles north from 

 New Milford, in Susquehanna Co. along the valley of Salt 

 Lick creek. Here a great dam of morainic debris was 

 thrown across the valley by the retreating ice, and piled up 

 100' to 150' above its level. The creek subsequently recut 

 a channel through the dam around the eastern portion of 

 the mass, leaving a great heap of the material west from the 

 present stream, and a small portion east of it. 



The section of this Drift heap, 90' high, made by the Dela- 

 ware, Lackawanna & Western railroad gravel quarry on the 

 east bank of the stream, exposes a perfect mass of sandstone 

 bowlders mostly Calskill, Chemung and Portage from 1" to 



*The limitation of northern bowlders to a small area in the four townships 

 cited above calls for some special explanation, quite apart from that of the 

 general covering of Local Drift spread over the rest of the region. It looks as 

 if they were dropped from the left (S. E.) flank of a great glacier on its way 

 southwestward across Bradford county. 



The glacier seems to have split against the butress of the Catskill mount- 

 ains; one arm descending the Hudson valley to overflow New Jersey; the 

 other arm slanting off S. 20° to 30° W., and flowing down the valle3's of the 

 Upper Delaware and Susquehanna rivers in New York into Bradford, Tio- 

 ga, and Potter counties in Pennsylvania, where it has left the long moraine 

 of Big Meadows at the Third Fork of Pine creek, and many other traces. 



